Insulation module, system and method for installation and manufacture

ABSTRACT

Disclosed is a pre-formed insulation module ( 310, 320 ) for insulating a process component having opposed longitudinally extending contacting surfaces ( 390 ) extending along a length thereof and terminal contacting surfaces ( 337, 387 ) at each end thereof comprising: a) at least one first inner insulation layer ( 314 ) being constituted of an insulation material having suitable thermal shock characteristic under cryogenic conditions and having one surface ( 314   d ) proximate or contacting with a component to be insulated; b) at least one second outer insulation layer disposed radially outwardly of said inner insulation layer ( 314 ); c) at least one water vapour barrier layer ( 319 ); d) a cladding layer ( 318 ).

FIELD OF THE INVENTION

This invention relates to an insulation module suitable for cryogenicapplications; a system of modules for insulating a component; a methodof manufacture of the insulation modules; and a method of installationof the insulation modules.

BACKGROUND TO THE INVENTION

The purpose of insulation is well known, it is to reduce the impact ofambient environmental conditions on desired temperature within theinsulated environment by reducing the heat transfer driving forcebetween the insulated and ambient environments. The insulation operationinvolves the location and fastening of layer(s) of insulating materials,which may be of the same or different nature, about the component to beinsulated. The installation may involve wrapping of an insulatingmaterial about the component but other constructions, for example panelconstructions, which are adhered or otherwise secured to the componentmay also be employed.

In the industrial context, the objectives of insulation of a componentinclude maintaining a desired temperature within that component; andpersonnel protection. Thus in a chemical plant, tanks and pipes may holdor carry materials such as solids, gases or liquids which must bemaintained within controlled temperature limits for efficient use withinthe process being conducted within the chemical plant.

Achievement of this objective is directly linked to the cost efficiencyof the chemical plant as heating and cooling costs may be substantialand may be reduced by effective insulation to prevent heat loss or gainfrom the insulated component.

Insulation of a chemical plant is an expensive process. Generally, ithas involved the installer in the transport of the necessary claddingand insulation materials to the site where it is then manufactured intothe desired form to complete the insulation job. Therefore, the processis time consuming and requires a great deal of organisation to becompetently and cost effectively carried out.

Development of suitable insulation materials for cryogenic processesposes a particular difficulty. Cryogenic plants in conventional use, forexample in gas processing, operate at temperatures well below thefreezing point of water. Indeed, temperatures may be −140° C. or lower.Therefore, insulation barriers in cryogenic plants are subject to highthermal shock or stress profiles making development of suitableinsulators very difficult.

By way of example, the temperature difference between the interior ofthe insulated component and the ambient environment may be of the orderof 200° C. such that expansion behaviour may be encountered in outerportions of the insulation and contraction behaviour may be encounteredin inner portions of the insulation.

Still further, the insulation barrier must avoid ingress of water which,on freezing, will cause loss of insulation capability and possibly moreserious problems including insulation failure. All these problems meanthat specific insulation techniques and materials are required incryogenic applications.

As with other insulation applications, major costs are encountered inthe installation operation as various insulation materials must befabricated on site to meet the requirements of the application.

SUMMARY OF THE INVENTION

It is the object of the present invention to provide insulation modules,systems and methods for the manufacture and installation of these whichavoid, to the maximum practical extent, the cost, technical and safetydisadvantages of current techniques while achieving the insulationobjective.

With this object in view, there is provided a pre-formed insulationmodule for insulating a process component having opposed longitudinallyextending contacting surfaces extending along a length thereof andterminal contacting surfaces at each end thereof comprising:

-   -   (a) at least one first inner insulation layer being constituted        of an insulation material having suitable thermal shock        characteristic under cryogenic conditions and having one surface        proximate to a surface of a component to be insulated,    -   (b) at least one second outer insulation layer disposed radially        outwardly of said inner insulation layer;    -   (c) at least one water vapour barrier layer; and    -   (d) a cladding layer, wherein said longitudinally extending        contacting surfaces include a portion formed by a portion of at        least one of said first inner insulation layer and said second        outer insulation layer.

By pre-formed is meant that the insulation module may be manufactured,as a complete insulating article, prior to transfer to, and installationat, a factory site. The factory site may be very remote to the sitewhere installation will take place. Such pre-fabrication of modules,which may be installed directly at the site, saves significant sitecosts and reduces the cost of the insulation project.

The pre-formed module may be made up of any desired number of insulatinglayer(s) and any desired number of cladding layer(s) though minimisingthe number of layers will facilitate accurate fabrication. Each layer isof nature and thickness appropriate to the application.

The insulating layers must firstly include, proximate the insulatedcomponent, and most advantageously in contact with it, at least onefirst inner insulation layer of an insulation material, ideally apolymeric foam which retains flexibility and does not embrittle atcryogenic temperatures. Such foam layer accommodates thermalexpansion/contraction behaviour of the insulated component and musttherefore have appropriate thermal shock characteristics at cryogenictemperatures. Exemplary of such an insulating material is a polyimidefoam.

Further second layer(s) of insulating materials of same or differentnature from the first layer(s) may be employed radially outwardly fromthe first insulation layer. Polyisocyanurate resin (PIR), polyurethaneor possibly other polymer foams, which may be harder than the firstlayer, may be employed for such further layers. Five or more suchinsulation layers may be provided, three or more of which may be formedof a polymeric foam. More advantageously, one or more of the insulationlayers may be formed integral to facilitate fabrication. For example,the layers radially outwardly disposed from the inner insulation layermay be integrated to reduce the number of layers of insulation.Typically, the PIR or polyurethane foam layer may be formed as a singlelayer.

One or more layers, which may be located between the first and secondlayers, or radially outwardly thereof form a water vapour barrier. Onesuch layer is preferably disposed radially outwardly of the second outerinsulation layer(s). At least one water vapour barrier layer may bedisposed between the cladding and a polymeric foam insulation layer.Metallic foils may be used as suitable barriers. Alternatively, apolymeric vapour barrier, such as Mylar or appropriately rated mastic,or suitable cladding having low water vapour transmission rate (“WVTR”)may be employed. The water vapour barrier may be reinforced with glassfibres or by other means.

Each of the plurality of insulation and water vapour barrier layers isbonded to adjacent insulation layers by suitable technique.Advantageously, adjacent insulation layers may be adhered to each otherby a suitable adhesive, rated to expected temperature of service.Mastics of various kinds may be suitable. As mastics are available atvarious temperature ratings, the mastic employed should be suitablyselected for temperature and WVTR at that temperature. Thus differentmastics may be required, one mastic being used to adhere outerinsulation layers and another mastic being employed for adhering innerinsulation layers.

The adhesion operation is one that must be conducted carefully asuniform application of adhesive is necessary across the contactingsurfaces of the outer insulation layers, if appropriate insulationbehaviour and avoidance of water vapour ingress is to be achieved.Meeting this requirement may necessitate manual application of theadhesive. Insulation materials may be blended together. The constructionof the pre-formed module will be dependent upon the nature of theinsulation job and the cost acceptability of the module.

The insulation layers must be fabricated having regard to stressprofile. Thermally induced stresses will exist in both the longitudinaland radial directions of the insulation module and effective insulationmust accommodate this. To this end, internal contraction/expansionjoints may be formed along the length of the module and, optionally andadvantageously, terminal contraction/expansion joints are formed, ateach of its ends in the terminal contacting surfaces.

The modules will usually include connection means which may be jointsallowing circumferential and longitudinal connection of respectiveadjacent modules such that no breaks occur in the insulation layer. Suchconnection means are formed in the longitudinal and terminal contactingsurfaces of the module. The joints, of any suitable profile, for examplea wave shape, are cut or otherwise formed in any number, or each, of thelayers of the module. The joints may be staggered relative to eachother. The joints are adhered together during installation using masticor other suitable adhesive. The joints are designed to complement jointsof modules intended to be adjacent. Other connection means may be formedin the cladding layer. Other fasteners, such as metal bands, may also beemployed in connection of adjacent modules. The water vapour barrierlayers may be arranged to overlap the longitudinal and circumferentialjoints.

The cladding layer may be formed to circumferentially overlap theinsulation layers at one first end of a module. The overlap or lapportion may be swaged to allow connection to an adjacent module. At theother end of the module, the insulation layer underlaps the claddinglayer in a design complementary to that of the first end. Some modulesmay be formed with longitudinally extending lap portions andcomplementary modules are formed without such lap portions.

Adjoining insulation modules are designed to achieve easy connection toone another for insulation of process components such as pipes and tanksmay involve connection of a number of modules.

In the case where the component to be insulated is a pipe or pipefitting, such as an elbow or T-joint, a pre-formed module may cover aportion of the pipe or pipe fitting. That module is connected to anothermodule or series of modules to complete the insulation of the pipe orpipe fitting. Conveniently, the modules in this instance, may besemi-cylindrical in geometry or part-circular in cross section thoughthe module may be a fractional cylinder of any desired circumferentialextent. It may be found that semi-cylindrical modules are suitable forinsulation of pipes to about 20″ diameter, above that diameter themodules may be made a lesser fraction of a cylinder in circumference.That is it may be found more convenient to use more than two modules toinsulate a length of pipe. It will be understood that the module neednot be limited in its application to the insulation of pipes, need notbe linear and may not be circular or part circular in cross-section.Many components, such as tanks, may be insulated using suitablepre-formed modules which need not be at all cylindrical in geometry. Thedetermining factors in selection of the design of the module are asfollows: the geometry of the component to be insulated, insulationrequirements and cost.

In a still further aspect of the present invention there is provided amethod of manufacturing an insulation module comprising forminginsulation layers of insulating material as described above; forming acladding material; assembling the cladding and insulation layerstogether; and forming the assembly into insulation modules forinsulating components.

In a still further aspect of the invention there is provided aninsulation system for insulating a process component comprised ofpre-formed modules of the invention described above, adjacent modulesbeing connected together by connection means as above described to formthe insulation system insulating the component.

In a still further aspect of the present invention there is provided amethod of insulating a component comprising manufacturing pre-formedmodules as above described; securing pre-formed modules to a component,or part of a component, and other modules insulating the components toenable insulation of that component or part of the component.

Pre-formed modules making up the insulation may be connected to one ormore adjacent module(s) and/or to the component or part of the componentas above described.

The insulation module may be secured into position by fitting onto thecomponent to be insulated. The fitting should take account of anythermal expansion and contraction of the insulated component. Modulescan be interference or otherwise fitted together. The connection meansmay be mechanical or chemical in nature but must be durable taking intoaccount environmental and plant conditions. For example, a chemicalconnection means such as an adhesive would require to be temperatureresistant, water resistant, and resistant to small leakage or smallplant concentrations of process materials. The connection means shouldallow water-tight sealing. Suitable sealants and tapes may be used forthis application. Bands may be tightened about the modules to facilitatefastening to a component to be insulated.

The module, system and method of installation forming aspects of thepresent invention present cost, efficiency and safety advantages oversystems and methods currently employed for insulation. Insulationmodules are also readily replaceable in the event of service failure.

BRIEF DESCRIPTION OF THE DRAWINGS

The various aspects of the invention may be more completely understoodfrom the following description of preferred embodiments thereof madewith reference to the accompanying drawings in which:

FIG. 1 is a side sectional view of a pre-formed module suitable forinsulation of a length of pipe made in accordance with one embodiment ofthe present invention;

FIG. 2 is an end view along line A—A of FIG. 3 of one end of two opposedpre-formed modules for insulating a pipe section in accordance with afirst embodiment of the present invention;

FIG. 3 is a side sectional view of the two opposed preformed modulesshown in FIG. 2;

FIG. 4 is an end view along line B—B of FIG. 3 of one end of the twoopposed pre-formed modules of FIGS. 2 and 3;

FIG. 5 is a side sectional view of two opposed preformed modulesaccording to the invention;

FIG. 6 is a side sectional view of two further opposed moduleslongitudinally adjacent to the modules of FIG. 5 prior to assembly;

FIG. 7 is a top perspective view showing the module of FIGS. 1 to 4 andits circumferential and longitudinally extending joints;

FIG. 8 is an end view of an outer insulation layer preform forfabrication into the module of FIGS. 1 to 7;

FIG. 9 is an end view of one end of the preform of FIG. 8 followingcutting of an end contraction/expansion joint;

FIG. 10 is an end view of polyimide preforms for installation into aninternal contraction/expansion joint of the module shown in FIGS. 1 to7;

FIG. 11 is an end view of two modules of a second embodiment of theinvention prior to assembly; and

FIG. 12 is an end view of two modules of a third embodiment of theinvention prior to assembly.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS OF THE INVENTION

Modules

Referring now to FIGS. 1 to 7, there are shown insulation modules 310and 320 suitable for use in cryogenic applications. Modules 310 and 320are designed to be connected together to insulate a length of pipe andaccordingly are part cylindrical and linear to achieve this task. Thepart-cylindrical linear geometry is not the only possible design formodules of the invention. The design of the module accommodates thespecial challenges inherent in cryogenic insulation. Chief of thesechallenges is the need to accommodate the high thermal stresses inducedby a temperature differential of some 200° C. to 250° C. between theinterior of insulated component and ambient environment.

Each module 310 and 320 has a first inner insulation layer 314 whichforms a thermal shock absorption layer suitable for cryogenicapplications and formed from a flexible polyimide foam. Inner insulationlayer 314 has an inner surface 314 d for contacting the pipe to beinsulated as well as longitudinal contacting surfaces 315 and terminalcontacting surfaces 315 a. A suitable polyimide foam is available underthe trade mark TA 301 SOLIMIDE supplied by Imi-Tech Corporation. Thislayer 314 will take up thermal expansion/contraction of the pipe. No gapis left to take up such expansion/contraction as left in conventionalpractice.

Second outer insulation layer 316 is disposed radially outwardly fromlayer 314 and is fabricated from a suitable polymeric foam such aspolyurethane or polyisocyanurate (PIR) foam for insulation applications.This layer 316 is formed with longitudinally extending contactingsurfaces 390 and terminal contacting surfaces 337, 387. Surfaces 390 areformed with flat surface portions 391.

Each layer is part-cylindrical, actually generally semi-cylindrical, inshape and each layer is co-axially disposed about a longitudinal axis ofeach module 310 and 320. The number and thickness of each of layers 314and 316 is selected in accordance with appropriate engineering standardshaving regard to the particular insulation application.

A water vapour barrier layer 319 is also disposed radially outwardlyfrom outer layer 316. The material of the layer 319 must have very lowwater vapour transmission rate (WVTR) and may be a metallic foil, suchas aluminium foil, polymeric film or laminate such as that availableunder the trade mark MYLAR. Mastics available under the trade nameFoster 60-38 or 60-39 may be used (WVTR 0.08 perm at 30 mils dry (0.05metric perm) Glass cloth, such as Foster No. 10, or glass or otherfibres may be used as reinforcement for the barrier material. A furtherwater vapour barrier layer, say of mastic, may overlap this.

The outermost cladding layer 318 may take the form of a metallic orpolymeric material such as aluminium or steel. A corrosion resistantmaterial is preferred. Alternatively, the cladding layer 318 may befabricated from a fireproofing material such as that available under theregistered trade marks CHARTEK, available from Chartek Inc; orTHERMALAG, available from Thermal Science Inc. Cladding layer 318 mayform a water vapour barrier layer.

Layers 314, 316 and 319 may be adhered or bonded together in anyappropriate way advantageously using a suitably selected adhesive whichmust be appropriately rated for the temperatures it will encounter inservice. The adhesive may advantageously be a water vapour barrier.Accordingly, an adhesive layer may be disposed between insulation layers314 and 316. Mastic may constitute the adhesive layer. The temperaturerating of the mastic is −29° C. to +121° C. and a suitable product isavailable under the trade mark 60-38 Foster or 60-39 Foster. Failure touse an appropriately rated adhesive may result in cold embrittlement,ice formation, delamination or some failure of the insulation module.

Foam insulation layer, 316 incorporates at least one suitable internalcontraction/expansion joint 370 formed along the length of modules 310and 320. Joint 370 may take the form of a part-cylindrical recess,occupied by a suitable flexible material part-circular, actuallysemi-circular, pre-form part 372 such as polyimide foam as abovedescribed, designed and arranged to accommodate expansion/contraction ofthe insulation layer 316 of modules 310 and 320. Part 372 neatly fitsthe recess of joint 370. As most contraction behaviour is observedinwardly of about one third of the distance from the insulation module310 surface to the component surface, the contraction/expansion joint370 need not extend to the surface. It terminates at a suitably locatedterminal end 371. Contraction/expansion joints, 334, 335 and 380 mayalso be formed at each end of module 310 and 320 in the terminalcontacting surfaces 337 and 387.

Modules 310 and 320 are fabricated with complementary longitudinaljoints 340, 342 and complementary circumferential joints 330, 334designed to respectively allow suitable secure connection of adjacentradially disposed modules 310 and 320 as well as longitudinally disposedmodules 310, 320 (as shown in FIG. 6). A number of jointing techniquesmay be used.

The complementary longitudinal profile joints having curved surfaces ofpeak 342/trough 340 kind, in which—on securement—peak 342 fits trough340, are cut into the longitudinally extending contacting surfaces 390of the modules, as conveniently shown for end 387 of modules 310 and 320in FIG. 9. Other profiles could be used.

At each end of the insulation module 310 and 320, foam insulation layers314 and 316 are fabricated with circumferential joints 330, 334 cut inthe terminal contacting surfaces 337 and 387 as shown in FIGS. 1 to 7.At one first end, circular section grooves 335 and 380 are cut intoterminal contacting surface 387 to form tongue portion 330. At the otherend, circular section groove 334 is cut into terminal contacting surface337 to form a complementary connection means to tongue portion 330 of anadjacent module (as seen in FIGS. 5 and 6). Other designs are possible.Each such circumferential joint is of appropriate design and sufficientarea to allow a good secure bond to be made between complementaryadjoining insulation layers of adjoining insulation modules with theappropriately temperature rated adhesive, advantageously a mastic.

Cladding layer 318 is formed to overlap insulation layer 316 at thefirst end, that end at which tongue portion 330 is formed. Insulationlayer 316 underlaps cladding layer 318 at the other end where insulationlayer 316 has an exposed portion 346. The overlap 322 is swaged to clipover one end of the cladding layer 318 of a longitudinally adjacentmodule 320 at installation (see FIG. 6). Both modules 310 and 320 havesuch a circumferential overlap portion 322. Module 320 additionally isformed with longitudinally extending overlap portion 322.

A flexible strip 324, for example of rubber such as butyl rubber orrubber of similar properties, is adhered on an inner surface of claddingsection 318 at the first end 387 of module 320 overlapping the jointbetween insulation layer 316 and overlap 322. It accommodates movementand forms part of an end contraction/expansion joint. Duringinstallation, strip 324 is to be adhered to exposed portion 346 ofinsulation layer 316 of a longitudinally adjacent module (see module 320of FIG. 6 which is longitudinally adjacent to module 320 of FIG. 5).

At the other end 337 of each module 310 and 320, insulation layer 316extends beyond the cladding layer 318 creating exposed portion 346. Onconnection to a longitudinally adjacent module, the cladding layer 318will be complete. In this regard, the overlap portions 322 which extendlongitudinally along module 320, may clip over cladding layer 318 of alongitudinally opposed module 310 of which cladding layer 318 issubstantially flush with longitudinally extending contacting surfaces390. Beads (not shown) may be appropriately formed along module 310 overwhich swaged portion 322 a of longitudinal overlap 322 engage to makemore secure connection.

On assembly, circular foam part(s) 381 and 382 are located in grooves335 and 380 to form the entire contraction/expansion joint at the firstend. These flat parts 381 and 382 may be formed from polyimide foam orother suitable material to accommodate service stress. At the other end,a circular foam part 336 is located in groove 334 to form the otherterminal contraction/expansion joint.

In another embodiment of this present invention, as shown for example inFIG. 11, the insulation layer 316 may be segmented into furtherinsulation sub-layers. All such sub-layers may be adhered together aswill be described further below. Each module 310 and 320 has a number oflayers: inner foam insulation layer 314, outer foam insulation layers316 and 316 b and a cladding layer 318. Water vapour barriers 319, 321,323 of suitable materials (as described herein) are also disposedbetween cladding layer 318 and foam insulation layer 316 b; and betweenfoam insulation layers 314, 316 a and 316 a, 316 b respectively. Allwater vapour barrier layers 319, 321, 323 must have very low watervapour transmission rate (WVTR) and may be fabricated from a metallicfoil such as aluminium foil or a polymeric film or laminate such as thatavailable under the trade mark MYLAR or mastics as above described.Glass cloth, Foster No. 10 glass cloth, could be used as reinforcementfor mastic. Insulation layer 314 is formed from polyimide foam.

Further insulation layers 316 a and 316 b are fabricated from apolymeric foam such as polyurethane or polyisocyanurate foam. Each layeris substantially cylindrical and co-axial. The thickness of each layeris approximately 50 mm, the exact thickness will be selected inaccordance with appropriate engineering standards.

Each foam insulation layer 314, 316 a, 316 b incorporates at least onesuitable contraction/expansion joint 370 designed and arranged toaccommodate expansion/contraction along the portion of pipe insulatedwith the insulation modules 310 and 320. It will be noted that eachcontraction/expansion joint 370 is staggered in longitudinal andcircumferential location relative to another. This arrangement is usedto allow secure jointing and minimum risk of water vapour ingress.

Each insulation layer 314, 316 a and 316 b is bonded to adjoininginsulation or water vapour barrier layer(s) by a suitable technique suchas adhesion. In the embodiment shown, each layer is bonded to itsadjacent layer by mastic adhesive.

Insulation and water vapour barrier layers 323, 316 b and 319 areadhered together by mastic having temperature rating −29° C. to +121° C.and available under the trade mark 60-38 Foster or 60-39 Foster.

As layers disposed inward of secondary water vapour barrier 323, that is314, 316 a and 322 are subject to colder temperatures, a differentmastic or adhesive having colder temperature rating is used. A suitableadhesive is available under the trade mark 60-96 Foster and has rating−190° C. to +120° C. Failure to use an appropriately rated adhesive mayresult in cold embrittlement delamination or some failure of theinsulation module.

Each foam insulation layer 314, 316 a and 316 b is fabricated with bothcircumferential joints of tongue and groove kind as above describedrelative to FIGS. 1 to 7, tongue 330 being shown in the drawing. Firstlongitudinal joints 362, 364, 366 and 367 are formed on longitudinallyextending surfaces 390 of module 320. Complementary longitudinal joints361, 363 and 365 are formed on longitudinally extending surfaces 390 ofmodule 310. These longitudinal joints form a square stepwise arrangementin contrast with the embodiment described with reference to FIGS. 1 to10. Joints 361 to 367, and the circumferential joints, are designed toallow suitable secure connection of adjoining modules 310 and 320 aswell as other modules not shown. A number of jointing techniques may beused. Water vapour barrier layers 321, 323 and 319 are arranged tooverlap each of these joints.

Each such joint is of appropriate design and sufficient area to allow agood secure bond to be made between complementary adjoining insulationlayers of adjoining insulation modules with the appropriatelytemperature rated adhesive, advantageously a mastic.

In an alternative embodiment, insulation layers 314 and 316 a may havedisposed between them a thin metallic foil, such as a silver foil, whichmay assist in the accommodation of thermal stresses.

FIG. 12 shows a construction in which insulation layers 316 a and 316 bare formed integral as one layer 316 of greater thickness. Theintervening adhesive/water vapour barrier layer 323 is omitted. Thejointing technique is the same as shown for FIG. 11.

The modules described with reference to FIGS. 1 to 7, 11 and 12 areavailable from Bains Harding Industries Pty Ltd under the trade markCRYO-LAG.

Method of Manufacture

The manufacture of the insulation modules 310 and 320 will be describedhereinbelow with reference to the preferred modules as shown in FIGS. 1to 7.

Firstly, are obtained polyimide preforms of semi-cylindrical shape toform the inner thermal shock layer 314. No joints need be formed inthese. The polyimide is as above described. Also are fabricated PIRsemi-cylindrical pre-forms 1316 of suitable length to form insulationlayer 316. These preforms 1316 have joining profile with peak 342/trough340 profile as shown in FIG. 8. Polyimide sections 372, of flatgeometry, as shown in FIG. 10, are formed to fit contraction/expansionjoints 370. These have the longitudinal joint profile of pre-forms 1316.Other materials could be used.

Polyimide flat circular half sections 336, 381 and 382, havingcomplementary shape and size to grooves 334, 335 and 380, to be formedas described below, are also prepared for the terminalcontraction/expansion joints.

Grooves 380 and 335 are cut into one end 387 of preforms 1316 as shownin FIG. 8 to form tongue 330. An internal circumferential groove 334,complementary to tongue 330, of suitable width and depth may then be cutinto the other end 337 of each of the PIR semi-cylindrical pre-forms1316 shown in FIG. 8. The end circumferential grooves 335 and 380, asshown in FIG. 3 occupied by polyimide half sections 381 and 382, arealso cut into the PIR pre-forms 1316. The PIR pre-forms 1316 may then beassembled and temporarily taped together.

Then are prepared sheet metal cladding sections to form cladding layer318 of each module 310 and 320. One such section may be formed with nolongitudinal lap and another may be formed with a longitudinallyextending lap longitudinal portion 322. Both sections are formed withcircumferential laps. The no lap piece is swaged at one of its ends andthe lap piece is swaged along three sides leaving one end unswaged. Acircumferential installation line 394 marking the end of overlap ofadjacent modules 310 and 320 is marked at preset distance from theunswaged end. A bead may be formed at this line for engaging withcircumferential lap portion 322 a. The section is then rolled toappropriate diameter.

Strips 324 of flexible material, for example, of rubber such as butylrubber, or other suitable materials 324 are then cut and bonded to theinside of the sheet metal section as shown in FIGS. 1, 5 and 6 with asuitable adhesive. Correct location of butyl rubber strips 324 andproper bonding to the sheetmetal is essential to accommodate movementand for proper function of the contraction/expansion joints.

Then an initial coat of adhesive, such as suitably rated mastic (watervapour barrier) as described above, may be applied to the surface of thePIR preforms 1316. Into the initial coat while still wet may be embeddeda layer of Foster's glass cloth Number 10 to form the, reinforced, watervapour barrier layer. A second coat of mastic of greater thickness isthen applied over the cloth. The longitudinal joints 340, 342 are not tobe covered with the mastic.

While the mastic is still wet the PIR pre-forms 1316 are covered withsheet metal forming cladding layer 318 leaving a certain length ofapproximately 50 mm exposed as shown in FIG. 1. The longitudinaloverlaps 322 on the lap section should be of the same length. Theassembly may then be cured for 24 hours. Fabrication is thensubstantially complete.

At that point, polyimide internal contraction/expansion sections 336,381, 382 may be inserted and bonded with mastic as described above intothe internal grooves 334, 335 and 380. Polyimide pre-forms 314 a arebonded into the corresponding PIR pre-forms 1316 to form the innerthermal shock layer 314.

The insulation module may be formed in lengths or customised to anyparticular component to be insulated, particularly for particularcomponents such as pipe fittings in a process plant though otherapplications for the module may be envisaged. A kit of modules could beformed by cutting the lengths to smaller convenient sizes on-site or inthe factory. These sub-modules are then available for installation atthe plant. It may be understood that lengths and number of modulesshould be convenient for cost-effective transport to site.

In the case of a bend or elbow, suitably shaped pre-form elements ofinsulation and cladding materials to accommodate the elbow are obtainedand assembled in the same manner of manufacture as modules 10 and 320with cutting of the modules to the requisite shape.

Method of Insulation

The installation method for a pipe or pipe fitting using the modules asdescribed with reference to FIGS. 1 to 10 proceeds as follows. It is tobe observed that other suitable techniques for insulation are possibleand the following description is not intended to be limiting.

Firstly, a bottom half “no longitudinal lap” module 310 may be fittedunder the pipe. A first adhesive, for example, mastic, available underthe trade mark Foster 60-38 or 60-39 is then applied to surface portions391 only of longitudinally extending contacting surfaces 390 of modules310 and 320 over the Foster No. 10 glass cloth reinforced water vapourbarrier layer 319. A joint sealant, mastic of same or differenttemperature rating to the first mastic, such as that available under thetrade mark Foster 95-50 may then be applied along the curved surfaces340, 342 forming the longitudinal joints in surfaces 390. Thelongitudinally extending contacting surface 315 of polyimide layer 314of module 310 is not to be covered with sealant. This will have a drycontact with the opposed surface 315 of upper adjacent module 320. Parts372 are inserted into internal contraction/expansion joints 370 of eachmodule to achieve a neat fit. Bonding may be used. Then the top lapmodule 320 may be loosely adhesively secured along the complementarylongitudinally extending contacting surfaces 390 and 391 to avoid breaksin insulation so that module 310 can not slide along the pipe.Longitudinal overlap portions 322 of module 320 may be clipped intoplace over cladding layer 318 of module 310. Joints may be taped.

Mastic is then applied to exposed portions of polyimide parts 381 and382, tongues 330 and exposed portions 324 a of butyl rubber strip 324 ofinstalled modules 310 and 320 (see FIG. 5). The previous steps arerepeated for the next pair of longitudinally adjacent modules (see FIG.6) such that longitudinal seams 375 are staggered relative to seams 375of the first portion 324 a of pair of modules. Module pair 310/320 (FIG.6), having terminal contacting surface 337 and exposed portions 346appropriately coated with mastic, excepting the circumferentialcontacting surface 315 a of layer 314, is slid, in the direction of thearrows, towards module pair 310/320 (FIG. 5) until the circumferentialinstallation line 394 is reached or a bead engages with circumferentialoverlap portion 322. This will have the effect of compressing parts 336of module 320 (FIG. 6) and parts 381, 382 of first module 320 (FIG. 5)with adhesion of adjacent modules at the complementary joints tongue 330and groove 334 and at the complementary terminal contacting surfaces 337and 387 of the adjacent module pair to avoid breaks in insulation.

Stainless steel bands may then be tightened on module pair constitutedby modules 310 and 320 (FIG. 5) such that an insulation barrier isproperly formed about the pipe to promote adhesion of the contactingsurfaces of adjacent insulation modules. It is to be remembered that drycontact is to be maintained at contacting surfaces 315, 315 a of theinner thermal shock layer 314 of all adjacent modules as well as atcontacting surfaces of parts 372 of the bottom and upper modules.

The above steps are then repeated for the bottom half of the nextsection of pipe. Fitting is commenced adjacent the previously describedassembly. In each case, the next module pair is appropriately prepared,as above, and slid towards the previously fitted module until thecircumferential installation line 394 has been reached compressing thepolyimide half-sections 381, 382 some distance. Longitudinal seams 375are staggered. After such fitting, stainless steel bands may betightened on the previous module pair.

The above steps are repeated until the installation operation iscomplete. Much the same process, allowing for differences in geometry,is conducted for components other than pipes.

Modifications and variations may be made to the present invention orconsideration of the disclosure by the skilled reader of thisdisclosure. Such modifications and variations are considered to fallwithin the scope of the present invention.

1. A pre-formed insulation module for insulating a process componenthaving opposed longitudinally extending contacting surfaces extendingalong a length thereof and terminal contacting surfaces at each endthereof comprising: (a) at least one first inner insulation layer beingconstituted of a flexible insulation material having a capacity towithstand thermal shock under cryogenic conditions and having onesurface proximate to a surface of a component to be insulated; (b) atleast one second outer insulation layer disposed radially outwardly ofsaid inner insulation layer; (c) at least one water vapour barrierlayer; (d) a cladding layer distinct from said at least one water vapourbarrier layer; and (e) at least one contraction/expansion jointpositioned between the ends of the module, said contraction/expansionjoint comprising a recess extending circumferentially around alongitudinal axis of said module and radially outwardly from said onesurface, said recess terminating in spaced apart relation to saidcladding layer and providing for longitudinal expansion and contractionof said insulation layers.
 2. The module of claim 1 including connectionmeans for connecting said module to an adjacent module for insulatingsaid component.
 3. The module of claim 2 wherein said connection meansare circumferentially and longitudinally disposed relative to alongitudinal axis of said module.
 4. The module of claim 3 wherein saidcircumferentially disposed connection means are formed in the terminalcontacting surfaces and the longitudinally disposed connection means areformed in said longitudinally extending contacting surfaces.
 5. Themodule of claim 3 wherein said connection means are tongue and groovejoints, complementary joints being formed at each end of the module. 6.The module of claim 4 wherein said connection means are tongue andgroove joints, complementary joints being formed at each end of themodule.
 7. The module of claim 1 wherein said inner insulation layer isformed from a first insulation material and said outer insulation layeris formed from a second insulation material said first insulationmaterial having substantially different thermal shock characteristicsfrom those of said second insulation material.
 8. The module of claim 7wherein said at least one insulation layer is formed of polyimide foam,then at least one outer layer is formed of polyisocyanurate resin andthe water vapour barrier layer, radially outwardly disposed from saidsecond outer insulation layer, is formed from a material selected fromthe group consisting of metallic foils, polymeric films, mastics, andfibre-reinforced such materials.
 9. The module of claim 1 wherein saidcontraction/expansion joint is a recess having a terminal end formed insaid at least one second outer insulation layer.
 10. The module of claim1 wherein a contraction/expansion joint is formed in terminal contactingsurfaces of the module at each end thereof.
 11. The module of claim 2wherein said inner insulation layer is formed from a first insulationmaterial and said outer insulation layer is formed from a secondinsulation material said first insulation material havinginsubstantially different thermal shock characteristics from those ofsaid second insulation material.
 12. The module of claim 3 wherein saidinner insulation layer is formed from a first insulation material andsaid outer insulation layer is formed from a second insulation materialsaid first insulation material having substantially different thermalshock characteristics from those of said second insulation material. 13.The module of claim 4 wherein said inner insulation layer is formed froma first insulation material and said outer insulation layer is formedfrom a second insulation material said first insulation material havingsubstantially different thermal shock characteristics from those of saidsecond insulation material.
 14. A pre-formed insulation module forinsulating a process component, said module comprising longitudinallyextending module portions having opposed longitudinally extendingcontacting surfaces extending along a length thereof and terminalcontacting surfaces at each end thereof, said module portionscomprising: (a) at least one first inner insulation layer beingconstituted of a flexible insulation material having a capacity towithstand thermal shock under cryogenic conditions and having onesurface proximate to a surface of a component to be insulated; (b) atleast one second outer insulation layer disposed radially outwardly ofsaid inner insulation layer; (c) at least one water vapour barrierlayer; (d) a cladding layer distinct from said at least one water vapourbarrier layer; and (e) a plurality of contraction/expansion jointspositioned between the ends of the module, said contraction/expansionjoints comprising recesses located in each of said module portions, saidrecesses in one said module portion being spaced apart longitudinallyrelative to said recesses in another said module portion, said recessesextending circumferentially around a longitudinal axis of said moduleand radially outwardly from said one surface, said recess terminating inspaced apart relation to said cladding layer and providing forlongitudinal expansion and contraction of said insulation layers.
 15. Apreformed insulation module according to claim 1, wherein said recessextends radially outwardly ⅔ of the distance between said one surfaceand said cladding layer.
 16. A preformed insulation module according toclaim 14, wherein said recesses extend radially outwardly ⅔ of thedistance between said one surface and said cladding surface.
 17. Themodule of claim 1, wherein said recess is occupied by a flexiblematerial.